| Abstract: | ABSTRACT: BACKGROUND: The interaction of a nanomaterial (NM) with a biological system depends not only on the sizeof its primary particles but also on the size, shape and surface topology of its aggregates andagglomerates. A method based on transmission electron microscopy (TEM), to visualize theNM and on image analysis, to measure detected features quantitatively, was assessed for itscapacity to characterize the aggregates and agglomerates of precipitated and pyrogenicsynthetic amorphous silicon dioxide (SAS), or silica, NM. RESULTS: Bright field (BF) TEM combined with systematic random imaging and semi-automatic imageanalysis allows measuring the properties of SAS NM quantitatively. Automation allows measuring multiple and arithmetically complex parameters simultaneously on high numbersof detected particles. This reduces operator-induced bias and assures a statistically relevantnumber of measurements, avoiding the tedious repetitive task of manual measurements.Access to multiple parameters further allows selecting the optimal parameter in function of aspecific purpose.Using principle component analysis (PCA), twenty-three measured parameters wereclassified into three classes containing measures for size, shape and surface topology of theNM. CONCLUSION: The presented method allows a detailed quantitative characterization of NM, like dispersionsof precipitated and pyrogenic SAS based on the number-based distributions of their meandiameter, sphericity and shape factor. |
